ASB Bank has launched a new six-month fixed mortgage rate but the deal is only available to customers with a deposit of at least 20 per cent.
Shaun Drylie, spokesman for ASB, said the bank's 4.75 per cent fixed rate was its "lowest ever".
To qualify, customers must have an ASB credit card, an active transactional account and at least 20 per cent equity.
Reserve Bank Governor Graeme Wheeler announced last week that banks would be subject to restrictions on high loan-to-value ratio (LVR) housing mortgage loans from October 1.
Banks will have to restrict new residential mortgage lending at LVRs of over 80 per cent to no more than 10 percent of the dollar value of their new housing lending flows.